Motorized assist system for wheelchair exercise apparatus

ABSTRACT

Motorized assist systems are provided which are operable to assist in initiating and ceasing the rotation of rollers of wheelchair treadmill systems, and to provide resistance to user-applied forces to facilitate effective exercise. In some embodiments, the motorized assist system includes a driving motor mechanically connected to one or more rollers of a wheelchair treadmill and a sensor. The sensor is configured to detect a rotational force or a rotational velocity of the roller(s) of the wheelchair treadmill. The driving motor is configured to exert a driving force on the roller in response to a detected rotational force on the roller or in response to a detected rotational velocity of the roller.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/694,793 filed on Jul. 6, 2018 and entitled “MOTORIZED ASSIST SYSTEM FOR WHEELCHAIR EXERCISE APPARATUS,” which application is expressly incorporated herein by reference in its entirety.

BACKGROUND

Exercise is an important activity for helping people get stronger, build endurance, reduce stress, and feel better. Exercise can be important for all types of people, including people who rely on the use of a wheelchair due to an injury or disability. Unfortunately, there are very few options for people in wheelchairs to perform exercise in traditional gyms. This can be particularly problematic when the individuals travel to hotels or seek treatment in medical facilities and there is no equipment for facilitating exercise in a wheelchair.

Some treadmills have been designed for enabling wheelchair users to perform exercise from their wheelchair. For instance, a wheelchair user may push their wheelchair onto a specialized treadmill platform and drive their wheelchair on the treadmill similarly to how people may walk or run on a traditional treadmill.

Some wheelchair treadmills include resistance elements, such as flywheels, which resist the forces that users apply to their wheelchair wheels to provide users with effective exercise. However, many wheelchair treadmill resistance elements are constantly engaged, requiring a large amount of force to initiate and stop an exercise session.

The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.

BRIEF SUMMARY

Disclosed embodiments are directed to exercise equipment, especially treadmills, which are configured for use with wheelchairs and which are further configured to provide motorized assistance to facilitate exercise.

In some embodiments, the disclosed treadmills include a platform for supporting a wheelchair, one or more rollers which are associated with the platform and configured to support one or more driving wheels of the wheelchair, and a motorized assist system including a driving motor mechanically connected to the one or more rollers and a sensor configured to detect a rotational force on the one or more rollers.

In some embodiments, the driving motor is configured to exert a driving force on the rollers in response to the sensor detecting a rotational force on the one or more rollers that exceeds a threshold force. In some instances, the threshold force is a function of a rotational velocity of the rollers.

In some embodiments, the driving motor exerts the driving force in the same direction as the rotational force detected by the sensor. In other embodiments, the driving motor exerts the driving force in a direction opposite the rotational force detected by the sensor.

In some embodiments, the sensor is configured to detect a rotational velocity of the one or more rollers.

In some embodiments, the driving motor is configured to exert a driving force on the one or more rollers in response to the sensor detecting that the rotational velocity of the one or more rollers reaches a threshold velocity. In some instances, the threshold velocity is a function of the rotational velocity of the one or more rollers.

In some embodiments, the driving motor exerts the driving force in the same direction as the rotational velocity detected by the sensor. In some instances, the driving motor exerts the driving force in a direction opposite the rotational velocity detected by the sensor.

Additional features and advantages will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the teachings herein. Features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the present invention will become more fully apparent from the following description and appended claims or may be learned by the practice of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and other advantages and features can be obtained, a more particular description of the subject matter briefly described above will be rendered by reference to specific embodiments which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments and are not therefore to be considered to be limiting in scope, embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 illustrates a racing/track wheelchair being placed on an example wheelchair treadmill embodying the subject invention;

FIG. 2 illustrates a perspective view of an example wheelchair treadmill embodying the subject invention;

FIG. 3 illustrates a front elevation view showing an example wheelchair treadmill;

FIG. 4 illustrates a back elevation view showing an example wheelchair treadmill;

FIG. 5 illustrates a top elevation view showing an example wheelchair treadmill;

FIG. 6 illustrates a bottom elevation view showing an example wheelchair treadmill that shows non-limiting and exemplary placements for motorized assist systems;

FIG. 7 illustrates an example embodiment of a motorized assist system for a wheelchair treadmill and a roller of a wheelchair treadmill;

FIG. 8 illustrates an example embodiment of power transmission mechanism that may be implemented to transmit the power generated by the motor to the roller(s); and

FIG. 9 illustrates an example user interface that allows a user to control the motorized assist system.

DETAILED DESCRIPTION

Disclosed embodiments are directed to exercise equipment, especially treadmills, which are configured for use with wheelchairs and which are further configured to provide motorized assistance to facilitate exercise.

In some embodiments, the disclosed treadmills include a platform for supporting a wheelchair, one or more rollers which are associated with the platform and configured to support one or more driving wheels of the wheelchair, and a motorized assist system including a driving motor mechanically connected to the one or more rollers and a sensor configured to detect a rotational force on the one or more rollers.

In some embodiments, the driving motor is configured to exert a driving force on the rollers in response to the sensor detecting a rotational force on the one or more rollers that exceeds a threshold force. In some instances, the threshold force is a function of a rotational velocity of the rollers.

In some embodiments, the driving motor exerts the driving force in the same direction as the rotational force detected by the sensor. In other embodiments, the driving motor exerts the driving force in a direction opposite the rotational force detected by the sensor.

In some embodiments, the sensor is configured to detect a rotational velocity of the one or more rollers.

In some embodiments, the driving motor is configured to exert a driving force on the one or more rollers in response to the sensor detecting that the rotational velocity of the one or more rollers reaches a threshold velocity. In some instances, the threshold velocity is a function of the rotational velocity of the one or more rollers.

In some embodiments, the driving motor exerts the driving force in the same direction as the rotational velocity detected by the sensor. In some instances, the driving motor exerts the driving force in a direction opposite the rotational velocity detected by the sensor.

The following now refers to an exemplary wheelchair treadmill into which the motorized assist systems described herein may be implemented. Although the disclosure will focus on implementation of the motorized assist systems into the wheelchair treadmill shown in FIGS. 1-5, it will be appreciated that these systems may be implemented into other wheelchair treadmills and/or other treadmills. For example, the systems described herein may be implemented into the wheelchair treadmills described in U.S. Pat. No. 6,645,127 and U.S. Patent Publication 2018/0071609, invented by Larry L. Pestes, which are incorporated herein by reference in their entireties, as well as any other wheelchair treadmill having one or more rollers that are powered by one or more motors to assist in the operation of the rollers, as described herein.

Track/Racing Wheelchair Embodiments

Referring now to FIG. 1, an example racing or track wheelchair 113 is placed on an example wheelchair treadmill 100. The racing wheelchair 113 includes two driving wheels 108 and a single front wheel 109 that is connected to the wheelchair with a central crossbar 110. Each of the driving wheels includes a hand rim 116. A user 114 pushes the hand rims 116 to drive the driving wheels forward.

The wheelchair treadmill 100 includes a platform 101, one or more rollers 102, a fastener assembly 103 coupled to the platform 101, and a receptacle 104. The one or more rollers 102 are exposed through the platform 101 for engaging the two driving wheels 108 of the wheelchair 113 during the use of the wheelchair treadmill 100. The receptacle 104 is attached to the platform 101 for receiving and restricting movement of the front wheel 109 in at least two directions, including (but are not limited to) the back-and-forth directions and/or the left-and-right directions. The fastener assembly 103 is configured with a clamp 106 for selectively clamping onto the crossbar 110 of the wheelchair and for securing the wheelchair 113 in a fixed location during use of the wheelchair treadmill 100.

In FIG. 1, the wheelchair treadmill 100 has a single roller 102. Both of the driving wheels 108 of the wheelchair 113 are in contact with the single roller 102. In another implementation, referring to FIG. 2, the wheelchair 200 includes two rollers 202, each of which supports one of the driving wheels of wheelchair. Having two separate rollers allows a user to selectively exercise one side of his or her body separately. Because having one side that is stronger than the other side of one's body is a fairly common problem, the two-roller implementation allows a user to strengthen the weaker side of body separately and/or set up different resistance for each side.

Each of the one or more rollers may be connected to a separate flywheel 208. A resistance may be imposed on each of the rollers and/or the flywheels selectively, such that a user may choose different exercise intensities for each side of their body.

Referring back to FIGS. 1 and 2, the wheelchair treadmill 100, 200 includes a receptacle 104, 204. The receptacle 104, 204 may include a trough 105, 205 that extends from a front end to a back end of the receptacle 104, 204. The receptacle 104, 204 may further include a stop 111, 211 disposed at the front end of the trough and configured to stop the front wheel 109 from rolling forward beyond the front end of the receptacle 104. The trough 105, 205 may be slidably mounted on the platform 101, 201 so that when the front wheel of the wheelchair presses up against the trough, it will slide forward. It may also have a spring (not shown) or other retractable device for retracting the trough back to an original resting position (shown in FIG. 2) when the wheelchair is removed from the treadmill 200.

The receptacle 104, 204 and the one or more rollers 102, 202 may be positioned at least partially above a top planar surface of the platform 101, 202 to facilitate exercise and movement of the driving wheels on the wheelchair without being obstructed by the platform.

It will be appreciated that the receptacle 104, 204 may include various different components. For example, referring to FIG. 2, the receptacle 204 may include a base 218 attached to the platform 201. A support member 219 may be further mounted on the base 218 forming a triangle support for the stop 211. The trough 205 and/or the stop 211 may be slidably mounted on the base 218, such that the trough 205 and/or the stop 211 may slide back-and-forth between a resting position (FIG. 2) and an extended position (FIG. 1).

Referring to FIG. 1, the wheelchair treadmill 100 may further include a ramp 115 mounted to the platform 101 near the back end of the trough 105. The ramp 115 is operable for facilitating loading and unloading the front wheel 109 onto the trough 105. For example, before the front wheel 109 is loaded onto the trough 105, trough 104 rests in close proximity to ramp 115 in a resting position such that the front wheel 109 may be driven up ramp 115 onto the trough 105 of the receptacle 104. After the front wheel 109 is loaded onto the trough 105, the receptacle 104 responds to continued forward motion of the front wheel 109 by sliding forward into an extended position (FIG. 1) as the front wheel 109 pushes against the stop 111.

The receptacle 104 may further include a back stop 112 placed near the back end of the trough 105. The back stop 112 is configured to stop the front wheel 109 from sliding backward beyond the back stop 112.

One side of the back stop 112 may be mounted to the back end of the trough 105, and the other side of the back stop 112 may be capable of rotating along the sagittal plane. When loading the front wheel 109 of the wheelchair 113 into the trough 103, the other side of the back stop 112 rotates down onto the platform 101 and/or connects to the ramp 115 extending the ramp 115 all the way to the trough 105 helping facilitate loading the front wheel 109 into the trough 105. After the front wheel 109 is loaded into the trough 105, the back stop 112 may be configured, in some instances, to rotate onto the trough 105, thereby forming a stop for stopping the front wheel 109 from sliding backwards while exercising. Similarly, after exercising is completed, the back stop 112 may rotates down onto the platform 101 again helping facilitate unloading the front wheel 109 out of the trough 105.

The back stop 112 may be slidably mounted on the trough 104. When loading or unloading the front wheel 109 of the wheelchair 113 into or out of the trough 103, the back stop 112 may slide down the trough and onto the platform 101, and/or connect to the ramp 115 extending the ramp 115 all the way to the trough 105 helping facilitating loading or unloading the front wheel 109 into or out of the trough 105.

As illustrated in FIGS. 1 and 2, the wheelchair treadmill 100, 200 includes a fastener assembly 103, 203. The fastener assembly 103 may consist of only a single clamp 106 configured for clamping onto any portion of the wheelchair 113, as opposed to the two clamp systems used for some other treadmill products. The single clamp can be beneficial for costing less than the two clamp systems. The single clamp system can also be configured to be selectively adjustable to clamp onto wheelchair frames/crossbars that have different diameters.

The fastener assembly 103, 203 may include an adjustable arm 117, 217 that is configured to slidably move horizontally between a left side and a right side of the wheelchair treadmill 100, 200. The fastener assembly 103, 203 may further be configured to move vertically, in a substantially perpendicular direction relative to the platform 101, 201. In some instances, the adjustable arm is also adjustable in length and/or configured to slide longitudinally along its length (e.g., fore and aft).

The wheelchair treadmill 100, 200 may further include an electronic control 107, 207 and power drivers for rotating the one or more rollers 102. In some implementations, the electronic control 107 is further configured to control a powered slide for selectively sliding the receptacle 104 between at least two different positions relative to the platform 101, such as the left-and-right directions and the front-and-back directions. The electronic control 107 is connected to a power supply (not shown).

The positioning and orientation of the fastener assembly may be adjustable manually by the user operating the wheelchair treadmill. Additionally or alternatively, the fastener assembly 103 may further include at least one electrically powered component for selectively controlling movement of the fastener assembly 103 in at least one direction, such as substantially horizontal directions and/or substantially vertical directions relative to the plane of the platform 101. The electrically powered component may be connected to the same electronic control 107.

Various structures may be implemented for mounting and/or constructing the fastener assembly 103. For example, referring to FIG. 2, the wheelchair 200 may further include a frame 220 attached to the front portion of the platform 201. The frame 220 may extend to both the left and right side of the platform 201. The height of the frame 220 may be an approximate eye level of a user sitting on the wheelchair while exercising. The height of the frame 220 may be adjustable to fit the user's height or eye level. The electronic control 107 may be tiltably mounted on the top of the frame 220, such that the angle of the electronic control 107 may be tilted/tiltable to a desirable angle facing the user.

The fastening assembly 203 may be mounted on the frame 220. As illustrated in FIG. 2, a pair of horizontal bars 221 and 222 are adjustably mounted on the frame 220, and the fastening assembly 203 is slidably mounted on the pair of horizontal bars 221, 222. The first horizontal bar 221 is attached on the frame 220. The left end of the first horizontal bar 221 is attached on the left side of the frame 220, and the right end of the first horizontal bar 221 is attached on the right side of the frame 220. The second horizontal bar 222 is connected to the first horizontal bar by one or more adjustable connector plates 223. One or more adjustable support members 224 (e.g., pistons) are configured to support the second horizontal bar 222. One end of the adjustable support member 224 is attached to a side of the frame 220. The other end of the adjustable support member 224 is attached to an end of the second horizontal bar 222. The length and the angle of the adjustable support member 224 is adjustable. When the adjustable support member 224 is extended longer, the side of the adjustable connector plate 223 that is attached to the support member 223 flexes up in a sagittal plane. Accordingly, the second horizontal bar 222 is raised up and also moved slightly forward following the connector plate 223. This is one way to move the clamp 206 (described below) up or down, relative to the treadmill platform 201.

The fastening assembly 203 is slidably mounted on the pair of horizontal bars 221, 222. The fastening assembly 203 is slidable in the left-and-right direction, relative to an orientation of the treadmill, along with the pair of horizontal bars 221, 222 to accommodate different positioning of the wheelchair crossbar. For example, if the clamp 206 is to be clamped onto a side portion of a traditional wheelchair, the clamp 206 would be adjusted to the side of the horizontal bars 221, 222 on which the portion of the wheelchair is located. Another example, if the clamp 206 is to be clamped onto a center crossbar of the wheelchair, the clamp 206 would be adjusted to the center of the horizontal bars 221, 222. When the desired horizontal position of the fastening assembly 203 is reached, the horizontal position of the fastening assembly 203 may be locked by rotating clamp handle 349, 449 (see FIG. 3, FIG. 4) into a locked position.

The fastening assembly 203 may include an adjustable arm 217 and a single clamp 206. The adjustable arm 217 is slidably and perpendicularly mounted to the pair of horizontal bars 221, 222. The single clamp 206 is attached to the back end of the adjustable arm 217. The length of the adjustable arm 217 may be adjustable, as such the location of the clamp may be adjusted in backward-and-forward directions relative to the treadmill platform 201. When the desired length of the adjustable arm 217 is reached, the length of the adjustable arm 217 may be locked by rotating clamping rod 339, 439 (see FIG. 3, FIG. 4) into a locked position.

Furthermore, when the adjustable support member 224 extends longer, the connector plates 223 flexes and raises the second horizontal bar 222. Accordingly, the adjustable arm 217 tilts, and the back end of the adjustable arm 217 raises the clamp 206 up higher. As such, the adjustable arm 117 is configured to move the clamp 206 vertically, in a substantially perpendicular direction relative to the platform 201.

The clamp 206 may be mounted to the adjustable arm 217 through a connector joint 225. The connector joint 225 may also be adjustable and further allow the angle of the clamp 206 to be adjusted based on the position and/or angle of a crossbar or frame of a wheelchair. For example, the front wheel of a racing wheelchair is often smaller than the two driving wheels, therefore, the front end of the crossbar that connects the front wheel is often lower than the back end of the crossbar that connects the back wheels, forming an angle relative to the platform 210. And, different wheelchairs may have different crossbar assemblies, therefore, the angles of the crossbar of different wheelchairs may be different. The adjustable connector joint 225 allows the clamp 206 to be adjusted to fit the angle of crossbars of different wheelchairs.

The clamp 206 is an adjustable toggle clamp including a toggle handle 226. The diameter of the clamp 206 may be adjusted to the approximate diameter of a crossbar of the wheelchair 200 first. Then, the clamp 206 may be further secured by pushing up or down the toggle handle 226 to secure the clamp 206 to the wheelchair crossbar.

FIG. 3 illustrates a front elevation view of an example wheelchair treadmill 300, which may correspond to the wheelchair treadmill 200 of FIG. 2. The wheelchair treadmill 300 includes a substantially horizontal platform 301. The left, right, front and back directions are based on a user's perception. Since FIG. 3 is a front elevation view of the wheelchair treadmill 300, the left and right side of FIG. 3 is opposite to the user's view, i.e., the left side of FIG. 3 is actually the right side of the user, and the right side of FIG. 3 is actually the left side of the user.

Two flywheels 308 are placed on the left and right side of the platform 301. A frame 320 is mounted on the top of the platform 301. The frame 320 includes left and right vertical portions 329 that are substantially vertically mounted on the left and right side of the platform 301. The frame 320 further includes a left and a right connection portions 330 that have a curved shape, connecting the left and right vertical portions to a horizontal portion 331. An electronic control 307 is mounted on the top of the horizontal portion 331. The flywheels 308 and the electronic control 307 may be powered by a same power source (not shown). One or more power cables may be extended through the frame 320 including the left and right vertical portions 329, the left and right curve shaped connection portions 330, and the top horizontal portion 331 to the electronic control 307.

A first horizontal bar 321 is attached to the left and right vertical portions 329 of the frame 320 by both left and right ends of the first horizontal bar 321. A second horizontal bar 322 is connected in parallel to the first horizontal bar 321 by a left and right connector plates 323 placed on each left and right end of the first and second horizontal bars 321, 322. A left and a right adjustable support member 324 are mounted on the frame 320 and are configured to support the second horizontal bar 322 on each left and right end of the second horizontal bar 322. The angle and the length of the adjustable support members 324 are both adjustable along the sagittal plane. When the length of the adjustable support members 324 extends longer, the second horizontal bar 322 raises and the angle of the adjustable support members 324 relative to the platform 301 increases.

A single clamp 303 is slidably mounted on the pair of horizontal bars 321, 322. Different configurations may be implemented to mount the clamp 303 onto the pair of horizontal bars 321, 322. For example, the clamp 303 may be mounted on an adjustable arm (not clearly shown), and the adjustable arm may be slidably and perpendicularly mounted on the one or both of the pair of horizontal bars 321, 322 by one or more bar mounts 332 that includes a clamping handle 349. The bar mount 332 may be tightened or loosened by rotating the clamping handle 349 into a locked position. When the bar mount 332 is loosened, the adjustable arm is slidable in the left-and-right direction between the left and right vertical portions 329 of the frame 320. When the bar mount 332 is tightened, the adjustable arm is being secured on the pair of horizontal bars 321, 322. A user may selectively secure the adjustable arm at any location between the left and right vertical portions 329 of the frame 320.

Furthermore, the adjustable support members 324 may further adjust the location of the clamp 303. When the adjustable support members 324 extend longer, the second horizontal bar 322 raises up, and also moves forward slightly towards the front of the exercising apparatus 300. Accordingly, the adjustable arm that is perpendicularly mounted on both of the horizontal bars 321, 322 tilts upward and raises the clamp 303 that is attached on the back end of the adjustable arm. As such, the clamp 303 is adjustable in substantially vertical directions relative to the treadmill platform.

The length of the adjustable arm may also be adjustable, thus, further adjust the location of the clamp 303 in the backward-and-forward directions relative to the treadmill platform. It is possible for the clamping rod 339 to be configured to fix the vertical adjustment of the clamp 303, in addition or as an alternative to locking the length of the adjustable arm.

Once the adjustable support members 324 is secured at a particular length and angle, the relative location of the adjustable arm on the horizontal bars 321, 322 is secured, and the length of the adjustable arm is secured, the location of the clamp 303 is secured. The configuration illustrated in FIG. 3 allows the location of the clamp 303 to be adjusted in all 3 dimensions including left-and-right directions, back-and-forth directions and vertical directions relative to the treadmill platform.

Additionally, as illustrated in FIG. 3, there may further be a connector joint 325 connecting the bar mount 322 and the clamp 303. The connector joint 325 may include a first and second vertical portions 334, 335, a first and second corner portions 336, 337, and a horizontal portion 338. The first vertical portion 334 may be adjustably secured on the first and second horizontal bars 321, 322 in a sagittal plane by a twistable handle 433 (see FIG. 4). A user may flex the first vertical portion 334 forward or backward to a desired position, e.g., a substantially vertical direction that is perpendicular to the platform 301. Once the first vertical portion 334 is adjusted to a desired position, a user may secure the first vertical portion 334 by tightening the twistable handle 433.

The first and second corner portions 336, 337 may be curve shaped to connect the vertical portions 334, 335 and the horizontal portion 338 together. The clamp 303 may be adjustably connected to the second vertical portion 335. The clamp 303 may be adjusted in any plane at any angle relative to the parallel bars 321, 322.

Each of the connections between the vertical portions 334, 335, corner portions 336, 337, and horizontal portion 338 may be adjustable. For example, the connection between the first vertical portion 334 and the first corner portion 336 may be adjustable in a transverse plane, such that the first vertical portion 334 would serve as a center axis, and the connector joint 325 including all the portions 335-338 would turn around the center axis in the transverse plane. The connection between the horizontal portion 338 and the second corner portion 337 may be adjustable in a sagittal plane; and the second corner portion 337 and the second vertical portion 335 may be adjustable in a transverse plane. Accordingly, the clamp attached to the connector joint 325 may be adjustable in all three dimensions, which allows clamping onto any portion of the wheelchair that may be placed at any angle and/or any plane relative to the platform.

The wheelchair treadmill 300 may also include a pair of front wheels 327, such that the exercising apparatus 300 may be moved easily. The wheelchair treadmill 300 may also include one or more adjustable front jacks 328 under the front portion of the platform 301. The front jacks 328 may be adjusted individually to keep the platform 301 substantially horizontal when placed on a non-flat surface.

FIG. 4 is a back elevation view of the exemplary wheelchair treadmill 400, which may correspond to the wheelchair treadmill 200 of FIGS. 2 and 300 of FIG. 3. Similar to FIG. 3, FIG. 4 shows a similar implementation of the fastener assembly of the wheelchair treadmill 400. The clamp 403 is adjustably mounted on the connector joint 425 that include a first and second vertical portions 434, 435, a first and second corner portions 436, 437 and a horizontal portion 438. From the back elevation view, several twistable handles are better illustrated. For example, the twistable handle 433 is configured to allow adjustment and securing of the first vertical portion 434 in the sagittal plane, and/or the connection between the first vertical portion 434 and the first connector portion 436 in the transverse plane; the twistable handle 440 is configured to adjust the diameter of the clamp 403 to the proximate diameter of a crossbar of wheelchair; and the toggle handle 426 is configured to further secure the crossbar in place.

As illustrated in FIG. 4, the wheelchair treadmill may further include one or more adjustable back jacks 441 under the back portion of the platform 401. Similar to the one or more front jacks 328 illustrated in FIG. 3, the back jacks 441 may also be adjusted individually to maintain the platform horizontal, especially when the wheelchair treadmill 400 is placed on a non-flat surface. The front and back jacks 328 and 441 may also be powered by the same power source (not shown), and be controlled by the same electronic controller 307, 407.

FIG. 5 illustrates a top elevation view of an example wheelchair treadmill, which may correspond to the wheelchair treadmill 200 of FIG. 2, 300 of FIG. 3, and/or 400 of FIG. 4. In this view, the two rollers 502 are better illustrated. The two rollers 502 are placed in two rectangular openings located at a back portion of the platform 501. In some implementations, the height of the two rollers 502 may be substantially level relative to the platform 501. In other implementations, the top of the two rollers 502 may be slightly above the platform 501 and at a similar level of the trough 505. The trough 505 is configured for securing the front wheel of the wheelchair in at least two directions (e.g., forward/backward and lateral right/left direction(s)). In some embodiments, when the rollers 502 and the trough 505 are placed at a substantially same level, the front wheel and the back wheels of the wheelchairs are level. As such, the user exercising on the wheelchair would feel as if he/she was exercising on a flat surface. In other embodiments, the trough is elevated or declined relative to the plane of the platform, to create a sensation of climbing up or down a hill during exercise. In some embodiments, the trough is connected to a control mechanism (not shown) for raising or lowering the trough.

In some embodiments, the height of the two rollers 502 may also be selectively adjustable to accommodate different climbing angles. For example, when loading or unloading the wheelchair onto the wheelchair apparatus 500, the height of the adjustable roller may be adjusted to be substantially the same level of the platform 501. Then, when the wheelchair is loaded to the trough 505 before exercising starts, the height of the adjustable roller may be adjusted higher (with the electronic control) to be at the level of the trough 505 or another level. In another embodiment, the height of each of the rollers may be adjusted independently to simulate a road condition, such as a bumpy road, or during a banked turn.

Motorized Assist Systems

Traditional wheelchair treadmills include resistance elements, such as flywheels, which resist the forces users apply to their wheelchair wheels when mounted to the wheelchair treadmill. Such flywheels are typically connected to the roller(s) of the wheelchair treadmill such that when a user applies a rotational force to their wheelchair wheels, and the rollers indirectly, the flywheel resists the user-applied force. However, such flywheels are constantly engaged. Often times, a large amount of force is required to overcome the flywheel resistance when the wheelchair treadmill rollers are at rest. A flywheel can also increase the force necessary to stop a wheelchair treadmill roller once the roller is already rotating. This can prove particularly problematic for wheelchair treadmill users with limited upper body strengths (e.g., the elderly). Additionally, flywheel elements are often bulky and/or heavy, which prevents optimization of the size and weight of wheelchair treadmills.

There is thus a need and desire for wheelchair treadmills that include a motorized assist system operable to assist in the starting and stopping roller rotation, provide resistance to user-applied forces, and/or eliminate the need for flywheel resistance elements altogether. Such devices would be useful, for example, to increase the usability of wheelchair treadmill systems, particularly for users with limited upper body strength. The systems described herein may be implemented to provide wheelchair treadmill manufacturers with an alternative to traditional flywheel resistance element, which may decrease the weight and/or size of wheelchair treadmills.

A motorized assist system of the disclosed embodiments includes one or more driving motors which are mechanically connected to the roller(s) of the wheelchair treadmill. A motorized assist system also includes one or more sensors, which are configured to sense the rotational force applied to the roller(s) and/or the rotational velocity of the roller(s).

Attention is directed towards FIG. 6, which shows exemplary locations on a bottom view of a wheelchair treadmill 600 where one or more motorized assist systems may be positioned. As illustrated in FIG. 6, the motorized assist system(s) may be positioned at the ends of rollers 602 of the wheelchair treadmill 600, as denoted by locations 651.

It will be appreciated that while FIG. 6 illustrates a view of a wheelchair treadmill that is specifically configured to accommodate three-wheeled track/racing wheelchairs (as described in FIGS. 1-5), the embodiments of the invention also apply to treadmills that are configured for use with traditional wheelchairs having four wheels. It will also be appreciated that although FIG. 6 illustrates a wheelchair treadmill with two rollers 602, the motorized assist systems of the present disclosure may be implemented into wheelchair treadmills with one or more than two rollers.

FIG. 7 illustrates a simplified schematic representation of a motorized assist system 753 of the present disclosure. As illustrated, the motorized assist system 753 is arranged adjacent to an end of a wheelchair treadmill roller 702, as described in FIG. 6.

In some embodiments, the motorized assist system 753 includes a driving motor, which is mechanically connected to one or more rollers 702, and a sensor.

In some embodiments, the sensor is configured to detect rotational forces applied to the roller 702 and/or the driving motor of the motorized assist system 753. In other embodiments, the sensor is configured to detect the rotational velocity of the roller 702 and/or the driving motor of the motorized assist system 753. In yet other embodiments, the sensor is configured to detect both rotational forces and rotational velocity on the roller 702 and/or the driving motor of the motorized assist system 753.

The sensor of the motorized assist system 753 may be configured, in some embodiments, to directly detect forces applied to the roller 702 and/or the driving motor in a variety of ways. For example, the sensor may include a radial arrangement of strain gauge load cells which include a flexible conductive material and are connected between a drive motor of the motorized assist system 753 and one or more rollers 702. When a force is applied to the load cells, the resistance of the flexible conductive material changes, which alters an output voltage proportional to the force applied. The sensor, therefore, may output a voltage which corresponds to the force applied to the driving motor and/or the roller 702

In another embodiment, the sensor of the motorized assist system 753 includes a capacitive load cell arranged such that the distance between the capacitance plates changes in response to rotational forces. It will be appreciated that other force sensing apparatuses, such as pneumatic load cells, hydraulic load cells, force-sensing resistors, piezoelectric accelerometers, and/or capacitance accelerometers may be utilized in addition or as an alternative to the force sensing apparatuses herein disclosed. It will furthermore be appreciated that any combination of force-sensing apparatuses may be utilized to directly detect the rotational force on a roller 702 and/or on a driving motor.

The sensor of the motorized assist system 753 may be configured, in some embodiments, to detect the rotational velocity of the roller 702 and/or the driving motor in a variety of ways. For example, the sensor may include a magnetic rotation sensor having a magnet attached to a rotating portion of the roller 702 and/or the driving motor of the motorized assist system 753, and a magnetic sensor in a static location such that the magnetic sensor detects each time the magnet revolves and passes the magnetic sensor per unit time (e.g., per second).

In other embodiments, the sensor utilizes electromagnetic induction to track the rotational velocity of the roller 702 and/or driving motor. For example, the sensor may include a magnetic element situated in/on the roller 702 or the driving motor with a surrounding conductive element, such when the magnetic element rotates with the roller 702 or driving motor, a current is induced in the surrounding conductive element proportional to the rotational velocity of the roller 702 or driving motor.

It will be appreciated that other mechanisms for sensing the rotational velocity not discussed herein in detail, such as eddy current or electronic speedometers, may be implemented into the sensor of the motorized assist system 753 of the present disclosure.

In some embodiments, the sensor of the motorized assist system 753 determines the rotational force exerted on the roller 702 and/or the driving motor of the motorized assist system 753 indirectly by utilizing the detected rotational velocity. For example, the sensor may detect a change in rotational velocity (e.g., a rotational acceleration) and calculate the rotational force on the roller 702 and/or the driving motor utilizing Newton's second law. Detecting rotational force indirectly (i.e., deriving the rotational force based on a detected change in the rotational velocity) provides several benefits including allowing the motorized assist system 753 to detect both rotational velocity and rotational force while only requiring detection hardware for detecting rotational velocity.

In some implementations, the sensor(s) of the motorized assist system 753 are controlled, powered, and/or in communication with an electronic control, such as electronic control 107, 207, 307, and/or 407 described above with respect to FIGS. 1 through 4, and which may include an interface, such as described in reference to FIG. 9, below. In some embodiments, the electronic control 107, 207, 307 and/or 407 receives data quantifying the detected rotational force and/or velocity of the roller 702 and/or the driving motor from the sensor(s). In other embodiments, the sensor outputs a voltage or other signal corresponding to the magnitude of the detected rotational force and/or velocity to the electronic control, the driving motor, or both.

As noted above, the motorized assist system 753 of the present disclosure includes a driving motor, which is mechanically connected to the roller(s) 702 of the wheelchair treadmill such that the driving motor is configured to exert a driving force on the roller(s) 702 of the wheelchair treadmill.

In some embodiments, the driving motor is a motor capable of applying a variable force to the rollers 702, such as a DC series motor, cumulative compound motor, slip ring induction motor, single-phase series motor, or repulsion motor. In other embodiments (such as where the motorized assist system 753 is only configured to help start/stop exercise sessions), the driving motor is a motor capable of applying a constant force to the rollers, such as a DC shunt motor, single- or multi-phase synchronous motor, squirrel cage induction motor, or capacitor start induction run motor.

The driving motor is, in some embodiments, powered and/or controlled by an electronic control, which may correspond to the electronic control 107, 207, 307, and/or 407 of FIGS. 1 through 4 and the interface of FIG. 9. For example, the electronic control may receive the detected rotational force and/or velocity of the roller 702 and/or driving motor from the sensor, and then the electronic control may operate the driving motor to exert a rotational force on the roller 702 based on the detected rotational force and/or velocity.

In other embodiments, the driving motor is in direct communication with the sensor(s) of the motorized assist system 753. For example, the driving motor may receive the detected rotational force and/or velocity directly from the sensor and then apply a rotational force on the roller 702 based on the detected rotational force and/or velocity.

Regardless of whether the driving motor is in direct communication with the sensor(s) or is controlled by the electronic control 107, 207, the driving motor may be configured to exert a rotational driving force on one or more rollers 702 of a wheelchair treadmill based on a number of modes of operation.

In one instance, the driving motor is configured to exert a driving force on the roller(s) 702 in response to the sensor detecting a rotational force of a certain magnitude. Put differently, the driving motor may be configured to exert a driving force when the sensor detects a rotational force on the roller(s) 702 and/or driving motor that exceeds a threshold force.

The driving motor may be configured to exert a rotational force on the roller(s) 702 in the same direction as the rotational force detected by the sensor. By way of non-limiting example, when the sensor detects an initial rotational force of sufficient magnitude applied by a user to a roller 702 at rest, the driving motor may exert a driving rotational force on the roller 702 in the same direction as the user-applied force to assist the user in increasing the rotational velocity of the roller 702 to a velocity suitable for exercise. In another instance, when the sensor detects a rotational force that opposes the current rotational velocity of the roller 702 (e.g., when the user desires to bring the exercise session to a halt), and the applied force exceeds the applicable threshold magnitude, the driving motor may exert a driving rotational force on the roller in the same direction as the user-applied force to assist in stopping the rotation of the roller 702.

Additionally, in some embodiments, the driving motor is configured to exert a rotational force on the roller(s) 702 in a direction that opposes the external rotational force applied to the roller(s) 702. For example, in some instances, when the user applies a force of sufficient magnitude on the rollers 702 during exercise, the driving motor applies a rotational force on the roller(s) 702 that opposes or resists the user-applied force to facilitate effective exercise.

In some embodiments, the applicable threshold force herein described is calculated dynamically as a function of the rotational velocity of the roller(s) 702 and/or the driving motor. For example, when the rotational velocity of the roller(s) 702 is low (e.g., when the roller is at rest or rotating slowly), the threshold velocity for activating the driving force of the driving motor is also low in order to provide easy access to drive motor assistance in initiating a workout session.

It will be appreciated that multiple threshold forces may be associated with certain rotational velocities. For example, when a roller 702 is rotating during an exercise session, a first threshold force magnitude may apply to forces detected in the same direction as the rotation direction of the roller 702, while a second threshold force magnitude may apply to forces detected in the direction opposite the rotation direction of the roller 702. Furthermore, the magnitude of the force that the driving motor exerts on the roller(s) 702 in a given direction may be based on the rotational velocity of the roller(s). In one example, these features allow the driving motor to exert a relatively powerful stopping force in response to a small detected external force in a direction opposite the rotation direction of the roller(s) 702 (e.g., when a user attempts to stop the rotation of the roller 702 during exercise), while still being configured to exert a relatively small resistive force in response to a large detected external force in the same direction as the rotation direction of the roller(s) 702 (e.g., when a user drives the roller during an exercise session).

In other instances, the driving motor is configured to exert a driving force on the roller(s) 702 in response to detecting that the rotational velocity of the roller(s) reaches and/or surpasses a threshold velocity. Several threshold velocities may be applicable to any particular exercise session. For example, a first threshold velocity may correspond to a low rotational velocity value, such that minimal user exertion is required to bring the roller 702 to the first threshold velocity. After the roller reaches the first rotational velocity, the driving motor may be configured to exert a rotational driving force in the same direction as the rotational velocity of the roller 702 to assist the user in further increasing the rotational velocity of the roller 702.

A second threshold velocity may correspond to a lower bound of a range of rotational velocities associated with a particular exercise intensity. In some embodiments, when the rotational velocity of the roller 702 reaches the second threshold velocity, the driving motor ceases to apply a driving force to the roller 702, allowing the user to drive the roller independently for exercise. A third threshold velocity may correspond to an upper bound of a range of rotational velocities associated with a particular exercise intensity. For example, if the user continues to drive the roller 702 such that the rotational velocity of the roller 702 exceeds the third threshold velocity, the driving motor may exert a driving force on the roller 702 in a direction that opposes the rotating direction of the roller 702, thus providing resistance against the exertions of the user for an effective exercise experience.

It will be appreciated that the aspects of the motorized assist systems 753 described herein, including sensor configurations and functionalities as well as the modes of operation of the driving motors, are applicable regardless of the exercise direction of the user. For example, the motorized assist system 753 of the present disclosure may be configured to assist users in initiating, stopping, and receiving exercise resistance during an exercise session in which the user drives their wheelchair wheels in reverse.

It will be appreciated that various combinations of the above-described sensor configurations and driving motor modes of operations of the motorized assist system 753 may be implemented into other wheelchair treadmill devices. As an illustrative example, a sensor of a motorized assist system 753 may detect an initial user-applied external force on a resting roller 702 of a wheelchair treadmill in a forward direction. Because the magnitude of the initial user-applied force exceeds a low threshold force necessary to activate the driving motor to assist in starting an exercise session, the driving motor of the motorized assist system 753 exerts a rotational force in the same direction as the initial user-applied force. The sensor then detects that the rotational velocity of the roller 702 reaches a first rotational velocity threshold which corresponds to a desired minimum exercise speed, which causes the driving motor to cease applying the rotational force in the same direction as the initial user-applied force. The user subsequently proceeds to apply exercise forces on the roller 702 in a forward motion by driving their wheelchair wheels in a forward motion. Because the rotational velocity of the roller 702 has exceeded the first rotational velocity threshold, the motorized assist system 753 responds to the user's exercise forces by exerting a resistive force on the roller 702 which is in a direction that opposes the user's exercise forces to facilitate effective exercise. Alternatively, when the user's exercise forces cause the rotational velocity of the roller 702 to exceed a second, upper-bound threshold, the motorized assist system responds by exerting a resistive force on the roller 702. When the user desires to end their exercise session, the user exerts a backward force on the roller 702 by exerting a backward force on their wheelchair wheels. Consequently, the motorized assist system 753 complements the user-applied backward force by exerting a rotational force on the roller 702 that opposes the rotational direction of the roller in order to cease the rotation of the roller and end the exercise session.

In other embodiments, the driving motor is configured to exert a rotational driving force on the roller(s) 702 independent of rotational force/velocity detected by the sensor(s) of the motorized assist system 753. For example, the electronic control 107, 207 may include user interface devices which receive user input. In some embodiments, the electronic control 107, 207 is configured to receive a user input for starting an exercise while the rollers 702 are at rest. In response to receiving such user input, the electronic control 107, 207 may cause the driving motor to exert a driving force on the roller 702 to initiate an exercise session without requiring the user to manually drive the rollers 702 up to rotational velocity suitable for an exercise session.

Similarly, the electronic control may receive user input, while the rollers 702 are already rotating, which is operable to stop an exercise session. In response to such user input, the electronic control 107, 207 may cause the driving motor to exert a driving force on the roller 702 to stop an exercise session without requiring the user to manually stop the rollers 702 from rotating.

Although much of the present disclosure has focused on utilizing a motorized assist system 753 to replace and/or eliminate the need for a flywheel resistance element, it will be appreciated that, in some embodiments, a motorized assist system may be utilized in conjunction with a flywheel element. For example, a motorized assist system may be implemented into a wheelchair treadmill system solely for the purpose of aiding users in the initiation and cessation of exercise sessions (e.g., to start/stop rotation of the rollers without requiring user exertion), while a flywheel resistance element is still utilized to resist user forces once the roller has reached exercising velocity.

Although FIG. 7 illustrates only a single motorized assist system 753 in relation to roller 702, it will be appreciated that any number of motorized assist systems 753 may be utilized with any number of wheelchair treadmill rollers 702. For example, two motorized assist systems may be connected to both ends of a single wheelchair treadmill roller. In another example, a single motorized assist system is connected on both sides of the motorized assist system to two different wheelchair treadmill rollers.

FIG. 8 further illustrates a few different example embodiments 800 of the power transmission mechanism, each of which may be implemented at the motorized assist system 753 of FIG. 7 for transmitting power generated from the motor to the rollers 702, and/or 802. As illustrated in FIG. 8, one or more motors 803 through 809 may be implemented to power the roller 802. The roller(s) 802 may correspond to the roller 702 of FIG. 7 and/or 602 of FIG. 6. The roller(s) 802 may include multiple rollers (e.g., a left roller and a right roller), and each of the multiple rollers may be powered independently by different motor(s) or be powered by a same set of motor(s). Each of the motor(s) may also receive power through an electrical plug from a wall socket, for example, not shown. The power from the electrical socket/outlet can also power the control interfaces/panels described herein. The electrical plug and wall outlets are not shown at this time, but are well understood/known by those of skill in the art.

In some embodiments, the roller 802 is powered by one or more in-wheel motors 806 and/or 807. In some embodiments, the roller 802 is powered by one or more out-wheel motors 803, 804 and/or 808. In some embodiments, a rotating shaft 810 is implemented to transmit power from the one or more motors 805 and/or 808 to the roller 802.

In some embodiments, a chain or belt 811 may be implemented to transmit power from one or more motors 803 and/or 804 to the roller 802. In some embodiments, a propeller shaft 812 may be implemented to transmit power from one or more motors 809 to the roller 802.

It is not intended that the scope of the invention be limited to only embodiments that exclusively utilize a single type of power transmitting mechanism or motor to transmit power from the one or more motors. In some embodiments, for example, a combination of rotating shaft, chain, belt and or propeller shaft may be implemented to transmit power from the one or more motors to the roller 802.

In some instances, each of the motors (e.g., motors 803 through 809) are controlled via a control panel. The control panel may correspond to the control 107 of FIG. 1, 207 of FIG. 2, 307 of FIG. 3, and/or 407 of FIG. 4, and the interface 900 of FIG. 9, which is mechanically connected to the wheelchair treadmill 100, 200, 300, and/or 400 and electrically connected to the motor(s) and/or sensor controls at the motor(s) (not shown) which control operation of the motor(s) in response to user input entered at the control panel.

In some alternative embodiments, the control panel may be a remote control that is detached from the treadmill 100, 200, 300, and/or 400 and which interfaces with sensor(s) (not shown), that are electrically coupled to the motor(s).

Alternatively, or in addition, the control panel may be an application that is installed at a user device, including, but are not limited to a mobile phone and a tablet.

FIG. 9 illustrates an example user interface 900 that may be displayed with the above described control panel. A user can interact with the user interface 900 to control the treadmill 100, 200, 300, and/or 400, including the motor assist related functions. As illustrated in FIG. 9, the user interface 900 may include a main menu 901. From the main menu 901, a user may navigate to a motor assist sub-menu 902. The motor assist sub menu 902 may include (but are not limited to) a sensitivity control 903, assist/resist control 904, and force applied control 905.

The sensitivity control 903 may be configured to control how sensitive the motor(s) 803 to 809 is to react to a user's push or pull indication. As described above, a driving force may be applied when the sensor detects that a rotational force on the one or more rollers that exceeds a threshold force. The threshold force can be defined by the user. For example, when the sensitivity value is adjusted to be higher, i.e., the sensor is highly sensitive, the threshold force would be lower. In such an instance, a user only needs to slightly push or pull the wheels, the motor(s) 803 through 809 will apply an assist or resist force to the roller 802. On the other hand, when the sensitivity value is adjusted to be lower, i.e., the sensor is less sensitive, the threshold force would be higher. In such a case, the user needs to push or pull the wheels harder to cause the motor(s) 803 through 809 to apply an assist or resist force to the roller 802.

As illustrated in FIG. 9, the sensitivity control 903 may include an up and a down button that allows a user to adjust the value of the sensitivity between a predetermined range (e.g., 1 through 10). In other instances, a user may enter a selected value into an input field (not shown), for receiving the sensitivity setting input.

The name “sensitivity control” and the layout of the sensitivity control 903 are merely an example configuration of a suitable control for controlling the sensitivity or the threshold force that triggers the application of the assist and resist force. For example, this control 903 may also be called “threshold force” control, and the predetermined choices may be “low”, “medium” and “high” instead of allowing a user to adjust a numerical number.

Further, the motor assist sub-menu 902 may also include an assist/resist control 904. The assist/resist control 904 is configured to allow a user to select whether an assist force or a resist force is to be applied. As illustrated in FIG. 9, an up and a down button may be implemented to allow a user to select between two options: Assist option and Resist option. Alternatively, or in addition, a numbering system may be utilized to enter a value into an input field for receiving the assist/resist force setting. For example, a positive number may indicate an amount of assist force that is to be applied to the roller 802; and a negative number may indicate an amount of resist force that is to be applied to the roller 802. Alternatively, or in addition, a separate force applied control 905 may be implemented to allow a user to adjust the assist or resist force that is to be applied to the roller 802.

Based on the user input received at the interface 900, the control panel transmits electrical signals to the motor(s) to control operation of the motor(s) according to the settings specified by the user at the interface.

As disclosed herein, various embodiments of a motorized assist system are provided, which are specifically configured to allow treadmills, including wheelchair treadmills with a single front wheel and two back driving wheels, to facilitate assisted initiation and cessation of exercise sessions, as well as provide exercise resistance without requiring a cumbersome flywheel resistance element. The embodiments disclosed include one or more sensors, which are configured to detect the rotational velocity and/or externally applied rotational forces of a roller and/or a driving motor. Disclosed embodiments also include a driving motor operable to exert a driving force on a roller of a wheelchair treadmill.

In some embodiments, the invention also extends to methods for receiving/detecting user input at a control and, in response, causing one or more motors to be activated to cause one or more corresponding rollers that are connected to the motor(s), which directly engage the wheel of a wheelchair, to rotate with a corresponding force and speed of rotation that corresponds to the user input.

The present invention may be embodied in other specific forms without departing from its spirit or characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A wheelchair treadmill comprising: a platform for supporting a wheelchair; one or more rollers associated with the platform and configured to support one or more driving wheels of the wheelchair; and a motorized assist system comprising: a driving motor mechanically connected to the one or more rollers; and a sensor configured to detect a rotational force on the one or more rollers.
 2. The wheelchair treadmill of claim 1, wherein the sensor is configured to detect a rotational force on the one or more rollers directly.
 3. The wheelchair treadmill of claim 1, wherein the sensor is configured to detect a rotational force on the one or more rollers indirectly.
 4. The wheelchair treadmill of claim 1, wherein the driving motor is configured to exert a driving force on the one or more rollers in response to the sensor detecting a rotational force on the one or more rollers that exceeds a threshold force.
 5. The wheelchair treadmill of claim 4, wherein the threshold force is a function of a rotational velocity of the one or more rollers.
 6. The wheelchair treadmill of claim 4, wherein the driving force is a function of a rotational velocity of the one or more rollers.
 7. The wheelchair treadmill of claim 4, wherein the driving motor exerts the driving force in the same direction as the rotational force detected by the sensor.
 8. The wheelchair treadmill of claim 4, wherein the driving motor exerts the driving force in a direction opposite the rotational force detected by the sensor.
 9. The wheelchair treadmill of claim 1, wherein the driving motor is controllable by a user-operated electronic control.
 10. The wheelchair treadmill of claim 9, wherein the user control is operable to activate the driving motor to exert a rotational force on the one or more rollers when the one or more rollers of the wheelchair treadmill are at rest.
 11. The wheelchair treadmill of claim 9, wherein the user control is operable to activate the driving motor to exert a rotational force on the one or more rollers that brings the one or more rollers to a halt when the one or more rollers of the wheelchair treadmill are initially rotating.
 12. The wheelchair treadmill of claim 1, wherein the driving motor is configured to exert a driving force on the one or more rollers in response to the sensor detecting that the rotational velocity of the one or more rollers reaches a threshold velocity.
 13. The wheelchair treadmill of claim 12, wherein threshold velocity is a function of the rotational velocity of the one or more rollers.
 14. The wheelchair treadmill of claim 12, wherein the driving motor exerts the driving force in the same direction as the rotational velocity detected by the sensor.
 15. The wheelchair treadmill of claim 12, wherein the driving motor exerts the driving force in a direction opposite the rotational velocity detected by the sensor.
 16. The wheelchair treadmill of claim 1, wherein the driving motor is controllable by a user-operated electronic control.
 17. The wheelchair treadmill of claim 16, wherein the user control is operable to activate the driving motor to exert a rotational force on the one or more rollers when the one or more rollers of the wheelchair treadmill are at rest.
 18. The wheelchair treadmill of claim 16, wherein the user control is operable to activate the driving motor to exert a rotational force on the one or more rollers that brings the one or more rollers to a halt when the one or more rollers of the wheelchair treadmill are initially rotating. 